In the census every person counted was also classified into one of three age-groups. These figures relate to the Indonesian part of the population only. The small groups of Chinese, Europeans, and other Asiatics were not considered.
The first age-group comprises those children that could not yet walk. This was at least a criterion easy to apply. They are children from 15 to 18 months of age at the outside. The size of this age-group indicates the birth-surplus of all children born in the previous 18 months diminished with the number of infants and toddlers, that died before 18 months of age. The size of this group totalled from 5 to 6 per cent. of the population.
The second group included the remaining non-adults. Nubility was taken for a criterion of adultness in the case of girls, which means an age-limit of round about 15. Girls married very young, but not yet nubile in a physical sense, were still counted for non-adult. As a criterion of adultness in boys was taken the ability to work, the point of time when boys start performing desa-services. Expressed in years this is a little later than marriageability viz. The 16th and 17th years of life. Hence this group is slightly larger as compared to the feminine group.
Third group, the adult population. The 1,528,868 Indonesians living in the D.I. Jogjakarta could be classified according to age-groups as follows Table II – 7.
Table II – 7
Age-groups of the Indonesian population of the D.I. Jogjakarta in 1930
The age-groups expressed in percentages of total population have been inserted in table II-7 also for the provinces Central_Java,West-Java, and East-Java for purposes of comparison. The non-adult-groups had practically the same size in the four areas compared: in Jogjakarta 42.1 per cent., in Central-Java 41.3 per cent., in West-Java 42.5 per cent., and in East-Java 40.9 per cent.